Aeromechanical Damping Measurement System for a Gas Turbine Engine

Abstract

A gas injection nozzle includes a nozzle housing, a pintle, and a piezoelectric actuator. The nozzle housing extends along an axis. The nozzle housing includes an inner wall, an outer wall, and an axial endwall. The inner wall and the outer wall form an outer cavity radially between the inner wall and the outer wall. The inner wall forms an inner cavity radially within the inner wall. The nozzle housing further forms a nozzle outlet passage through the axial endwall along the axis. The nozzle outlet passage is connected in fluid communication with the outer cavity by a gap at the first axial endwall. The pintle extends along the axis within the inner cavity and further forms the gap. The pintle is axially movable to vary a size of the gap. The piezoelectric actuator is coupled with the pintle and configured to move the pintle.

What is claimed is: 
     
         1 . A gas injection nozzle for an aeromechanical damping measurement system, the gas injection nozzle comprising:
 a nozzle housing extending along an axis, the nozzle housing includes an inner wall, an outer wall, and a first axial endwall, the inner wall and the outer wall extend circumferentially about the axis, the inner wall and the outer wall form an outer cavity radially between the inner wall and the outer wall, the inner wall forms an inner cavity radially within the inner wall, the nozzle housing further forms a nozzle outlet passage through the first axial endwall along the axis, the nozzle outlet passage is connected in fluid communication with the outer cavity by a gas flow control gap at the first axial endwall;   a pintle extending along the axis within the inner cavity, the pintle further forms the gas flow control gap, the pintle is axially movable between a first position and a second position to vary a size of the gas flow control gap; and   a piezoelectric actuator coupled with the pintle, and the piezoelectric actuator is configured to move the pintle between the first position and the second position.   
     
     
         2 . The gas injection nozzle of  claim 1 , wherein the piezoelectric actuator is configured to move the pintle between the first position and the second position at a frequency greater than 500 hertz. 
     
     
         3 . The gas injection nozzle of  claim 1 , wherein
 the inner wall circumscribes and is radially spaced from the pintle; and   the outer wall circumscribes and is radially spaced from the inner wall.   
     
     
         4 . The gas injection nozzle of  claim 1 , further comprising a flexure disk disposed between and contacting the pintle and the piezoelectric actuator, and the flexure disk further forms the inner cavity. 
     
     
         5 . The gas injection nozzle of  claim 4 , wherein the flexure disk is imperforate. 
     
     
         6 . The gas injection nozzle of  claim 4 , wherein the flexure disk forms a plurality of apertures extending through the flexure disk. 
     
     
         7 . The gas injection nozzle of  claim 1 , further comprising a flexure disk disposed between and contacting the pintle and the piezoelectric actuator, wherein the nozzle housing further includes a barrier wall axially between the first axial endwall and the flexure disk, and the barrier wall is configured with a slip fit around a shaft of the pintle. 
     
     
         8 . The gas injection nozzle of  claim 7 , wherein the barrier wall isolates the flexure disk from fluid communication with the inner cavity. 
     
     
         9 . The gas injection nozzle of  claim 7 , wherein the barrier wall extends between and to the inner wall and the pintle. 
     
     
         10 . The gas injection nozzle of  claim 7 , wherein the barrier wall forms a disk cavity axially between the barrier wall and the flexure disk, and the disk cavity is vented to an exterior of the gas injection nozzle. 
     
     
         11 . The gas injection nozzle of  claim 1 , wherein the nozzle housing further includes a second axial endwall forming the outer cavity opposite the first axial endwall, the nozzle housing forms an inlet cavity, and the second axial endwall forms a plurality of apertures connecting the outer cavity and the inlet cavity in fluid communication. 
     
     
         12 . The gas injection nozzle of  claim 1 , wherein the inner cavity is connected in fluid communication with the outer cavity by a gap formed between the pintle and the inner wall. 
     
     
         13 . An aeromechanical damping measurement system comprising:
 a gas injection nozzle including a nozzle housing, a pintle, and a piezoelectric actuator,
 the nozzle housing extends along an axis, the nozzle housing includes an inner wall and an outer wall, the inner wall and the outer wall extend circumferentially about the axis, the inner wall and the outer wall form an outer cavity, the inner wall forms an inner cavity radially within the inner wall, the nozzle housing further forms a nozzle outlet passage, the nozzle outlet passage is connected in fluid communication with the outer cavity by a gas flow control gap; 
 the pintle is disposed within the inner cavity, the pintle further forms the gas flow control gap, the pintle is axially movable between a first position and a second position to vary a size of the gas flow control gap, and 
 the piezoelectric actuator is coupled with the pintle, and the piezoelectric actuator is configured to move the pintle between the first position and the second position; 
   a gas source connected in fluid communication with the outer cavity, and the gas source is configured to direct a pressurized gas into the outer cavity; and   a controller electrically connected to the piezoelectric actuator, and the controller is configured to direct a control current to the piezoelectric actuator to control the piezoelectric actuator to position the pintle in the first position or the second position.   
     
     
         14 . The aeromechanical damping measurement system of  claim 13 , wherein the inner cavity is connected in fluid communication with the outer cavity by a gap formed between the pintle and the inner wall. 
     
     
         15 . The aeromechanical damping measurement system of  claim 13 , wherein the gas source is connected in fluid communication with the inner cavity by a pressure regulator, and the pressure regulator is configured to pressurize the inner cavity at a reduced pressure relative to the outer cavity. 
     
     
         16 . The aeromechanical damping measurement system of  claim 13 , wherein the controller includes a processor connected in signal communication with a non-transitory memory storing instructions which, when executed by the processor, cause the controller to:
 control the control current directed to the piezoelectric actuator to move the pintle between the first position and the second position at a frequency greater than 500 hertz.   
     
     
         17 . The aeromechanical damping measurement system of  claim 13 , further comprising at least one position sensor connected in signal communication with the controller, wherein the controller includes a processor connected in signal communication with a non-transitory memory storing instructions which, when executed by the processor, cause the controller to:
 control the control current directed to the piezoelectric actuator to move the pintle to control the size of the gas flow control gap and direct a pressurized gas stream into a component; and   measure a vibration of the component in response to the pressurized gas stream with the at least one position sensor.   
     
     
         18 . The aeromechanical damping measurement system of  claim 17 , wherein controlling the control current directed to the piezoelectric actuator to move the pintle to control the size of the gas flow control gap includes controlling the control current directed to the piezoelectric actuator to move the pintle between the first position and the second position at a frequency greater than 500 hertz. 
     
     
         19 . The aeromechanical damping measurement system of  claim 13 , wherein the gas injection nozzle further includes a flexure disk disposed between and contacting the pintle and the piezoelectric actuator, and the flexure disk further forms the inner cavity. 
     
     
         20 . The aeromechanical damping measurement system of  claim 13 , wherein the gas injection nozzle further includes a flexure disk disposed between and contacting the pintle and the piezoelectric actuator, the nozzle housing further includes a barrier wall axially between the first axial end wall and the flexure disk, the barrier wall isolates the flexure disk from fluid communication with the inner cavity, and the flexure disk forms a plurality of apertures extending through the flexure disk.